We describe the public release of Cluster Monte Carlo Code (CMC) a parallel, star-by-star $N$-body code for modeling dense star clusters. CMC treats collisional stellar dynamics using H\'enon's method, where cumulative effect many two-body encounters is statistically reproduced as single effective encounter between nearest-neighbor particles on relaxation timescale. The approach allows inclusion additional physics, including strong gravitational three- and four-body encounters, tidal...

Black holes formed in dense star clusters, where dynamical interactions are frequent, may have fundamentally different properties than those through isolated stellar evolution. Theoretical models for single evolution predict a gap the black hole mass spectrum from roughly $40-120\,M_{\odot}$ caused by (pulsational) pair-instability supernovae. Motivated recent LIGO/Virgo event GW190521, we investigate whether with masses within or excess of this "upper-mass gap" can be dynamically young...

Hierarchical triples are expected to be produced by the frequent binary-mediated interactions in cores of globular clusters. In some these triples, tertiary companion can drive inner binary merger following large eccentricity oscillations, as a result eccentric Kozai-Lidov mechanism. this paper, we study dynamics and rates black hole (BH) hierarchical formed via binary--binary encounters CMC Cluster Catalog, suite cluster simulations with present-day properties representative Milky Way's We...

We explore the possibility that GW190412, a binary black hole merger with non-equal-mass ratio and significantly spinning primary, was formed through repeated mergers in dense super star cluster. Using combination of semi-analytic prescriptions for remnant spin recoil kick mergers, we show mass GW190412 are consistent whose primary component has undergone two successive from population $\sim 10M_{\odot}$ holes high-metallicity environment. then production GW190412-like analogs CMC Cluster...

Abstract The theory of stellar escape from globular clusters (GCs) dates back nearly a century, especially the gradual evaporation GCs via two-body relaxation coupled with external tides. More violent ejection can also occur strong gravitational scattering, supernovae, wave-driven mergers, tidal disruption events, and physical collisions, but comprehensive study many mechanisms has been limited. Recent exquisite kinematic data Gaia space telescope revealed numerous streams in Milky Way (MW)...

ABSTRACT We present a novel, few-body computational framework designed to shed light on the likelihood of forming intermediate-mass (IM) and supermassive (SM) black holes (BHs) in nuclear star clusters (NSCs) through successive BH mergers, initiated with single seed. Using observationally motivated NSC profiles, we find that probability an ${\sim }100\hbox{-}\mathrm{M}_\odot$ grow beyond }1000 \, \mathrm{M}_\odot$ mergers ranges from }0.1~{{\ \rm per\ cent}}$ low-density, low-mass nearly 90...

We present a set of 148 independent N-body simulations globular clusters (GCs) computed using the code CMC (Cluster Monte Carlo). At an age ∼10–13 Gyr, resulting models cover nearly full range cluster properties exhibited by Milky Way GCs, including total mass, core and half-light radii, metallicity, galactocentric distance. use our to investigate role that stellar-mass black holes play in process collapse. Furthermore, we study how dynamical interactions affect formation evolution several...

Abstract Recent discoveries of black hole (BH) candidates in Galactic and extragalactic globular clusters (GCs) have ignited interest understanding how BHs dynamically evolve a GC the number ( <?CDATA ${N}_{\mathrm{BH}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mi>BH</mml:mi> </mml:msub> </mml:math> ) that may still be retained by today’s GCs. Numerical models show even if stellar-mass are GCs,...

Abstract Recent observations of globular clusters (GCs) provide evidence that the stellar initial mass function (IMF) may not be universal, suggesting specifically IMF grows increasingly top-heavy with decreasing metallicity and increasing gas density. Noncanonical IMFs can greatly affect evolution GCs, mainly because high end determines how many black holes (BHs) form. Here we compute a new set GC models, varying within observational uncertainties. We find GCs lose most their few gigayears...

Since the first signal in 2015, gravitational-wave detections of merging binary black holes (BBHs) by LIGO and Virgo collaborations (LVC) have completely transformed our understanding lives deaths compact object binaries, motivated an enormous amount theoretical work on astrophysical origin these objects. We show that phenomenological fit to redshift-dependent merger rate BBHs from Abbott et al. (2020) is consistent with a purely dynamical for objects, current LVC could be explained entirely...

Abstract Very massive stars (VMSs) formed via a sequence of stellar collisions in dense star clusters have been proposed as the progenitors black hole seeds. VMSs could indeed collapse to form intermediate-mass holes, which would then grow by accretion become supermassive holes observed at centers galaxies and powering high-redshift quasars. Previous studies investigated how different cluster initial conditions affect formation VMS, including mass segregation, collisions, binaries, among...

Abstract The globular cluster 47 Tucanae (47 Tuc) is one of the most massive star clusters in Milky Way and exceptionally rich exotic stellar populations. For several decades it has been a favorite target observers, yet computationally very challenging to model because its large number stars ( N ≳ 10 6 ) high density. Here we present detailed self-consistent Tuc models computed with Cluster Monte Carlo code CMC ). include all relevant dynamical interactions coupled binary evolution,...

Abstract We explore three-body binary formation (3BBF), the of a bound system via gravitational scattering three initially unbound bodies (3UB), using direct numerical integrations. For first time, we consider systems with unequal masses, as well finite-size and post-Newtonian effects. Our analytically derived encounter rates results reproduce 3BBF rate predicted by Goodman &amp; Hut for hard binaries in dense star clusters. find that occurs overwhelmingly through nonresonant encounters two...

As ancient, gravitationally bound stellar populations, globular clusters are abundant, vibrant laboratories characterized by high frequencies of dynamical interactions coupled to complex evolution. Using surface brightness and velocity dispersion profiles from the literature, we fit $59$ Milky Way models \texttt{CMC Cluster Catalog}. Without doing any interpolation, without directed effort particular cluster, $26$ well-matched at least one our models. We discuss in core-collapsed NGC 6293,...

Abstract The existence of black holes (BHs) with masses in the range between stellar remnants and supermassive BHs has only recently become unambiguously established. GW190521, a gravitational wave signal detected by LIGO/Virgo Collaboration, provides first direct evidence for such intermediate-mass (IMBHs). This event sparked continues to fuel discussion on possible formation channels massive BHs. As detection revealed, IMBHs can form via binary mergers “upper mass gap” (≈40–120 M ⊙ )....

Abstract Recent numerical simulations of globular clusters (GCs) have shown that stellar-mass black holes (BHs) play a fundamental role in driving cluster evolution and shaping their present-day structure. Rapidly mass-segregating to the center GCs, BHs act as dynamical energy source via repeated superelastic scattering, delaying onset core collapse limiting mass segregation for visible stars. While recent discoveries BH candidates Galactic extragalactic GCs further piqued interest...

Abstract We apply for the first time orbit-averaged Monte Carlo star cluster simulations to study tidal tail and stellar stream formation from globular clusters (GCs), assuming a circular orbit in time-independent spherical Galactic potential. Treating energetically unbound bodies—potential escapers (PEs)—as collisionless enables this fast but spherically symmetric method capture asymmetric extratidal phenomena with exquisite detail. Reproducing features such as epicyclic overdensities, we...

Recently, \citet{vitral2021does} detected a central concentration of dark objects in the core-collapsed globular cluster NGC 6397, which could be interpreted as subcluster stellar-mass black holes. However, it is well established theoretically that any significant number holes would provide strong dynamical heating and fundamentally inconsistent with this cluster's profile. Claims intermediate-mass clusters should similarly treated suspicion, for reasons have been understood many decades....

Abstract Numerical and observational evidence suggests that massive white dwarfs dominate the innermost regions of core-collapsed globular clusters by both number total mass. Using NGC 6397 as a test case, we constrain features dwarf populations in clusters, at present day throughout their lifetimes. The dynamics these subsystems have astrophysical implications. We demonstrate collapse cluster cores is ultimately halted dynamical burning binaries. predict local universe yield merger rate...

We explore three-body binary formation (3BBF), the of a bound system via gravitational scattering three initially unbound bodies (3UB), using direct numerical integrations. For first time, we consider systems with unequal masses, as well finite-size and post-Newtonian effects. Our analytically derived encounter rates results reproduce 3BBF rate predicted by Goodman & Hut (1993) for hard binaries in dense star clusters. find that occurs overwhelmingly through nonresonant encounters two most...

We apply for the first time Monte Carlo star cluster modeling method to study tidal tail and stellar stream formation from globular clusters, assuming a circular orbit in smooth Galactic potential. Approximating energetically unbound bodies (potential escapers; PEs) as collisionless enables this fast but spherically symmetric capture asymmetric phenomena with unprecedented detail. Beyond reproducing known features, including epicyclic overdensities, we show how 'returning tails' may form...

Abstract Depending on the stellar type, more than 15% of stars in field have at least two companions. Hierarchical triple systems can be assembled dynamically dense star clusters, as a result few-body encounters among and/or compact remnants cluster core. In this paper, we present demographics and compact-object triples formed via binary–binary CMC Cluster Catalog , suite simulations with present-day properties representative globular clusters (GCs) observed Milky Way. We show how initial...

Many recent observational and theoretical studies suggest that globular clusters (GCs) host compact object populations large enough to play dominant roles in their overall dynamical evolution. Yet direct detection, particularly of black holes neutron stars, remains rare limited special cases, such as when these objects reside close binaries with bright companions. Here we examine the potential microlensing detections further constrain dark populations. Based on state-of-the-art GC models...

We present a novel, few-body computational framework designed to shed light on the likelihood of forming intermediate-mass (IM) and supermassive (SM) black holes (BHs) in nuclear star clusters (NSCs) through successive BH mergers, initiated with single seed. Using observationally motivated NSC profiles, we find that probability ${\sim}100 \, M_\odot$ grow beyond ${\sim}1000 mergers ranges from ${\sim}0.1\%$ low-density, low-mass nearly $90\%$ high-mass, high-density clusters. However, most...

Very massive stars (VMSs) formed via a sequence of stellar collisions in dense star clusters have been proposed as the progenitors black hole seeds. VMSs could indeed collapse to form intermediate-mass holes (IMBHs), which would then grow by accretion become supermassive observed at centers galaxies and powering high-redshift quasars. Previous studies investigated how different cluster initial conditions affect formation VMS, including mass segregation, collisions, binaries, among others. In...